Porous Semipermeable Membrane for Biosensor Diffusion and Adhesion
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Solution Overview
Problem
Existing polymer semipermeable membranes in biosensors face challenges with diffusion rate control, adhesion to sensor surfaces, and stability due to hydrophilicity and thickness issues, leading to inconsistent performance and potential peeling.
Innovation Solution
A method involving a mixed solution of hydrophobic polynorbornene polymer and hydrophilic small-molecule crosslinking agents is applied to the biosensor electrode, forming a porous structure through phase separation and crosslinking, allowing controlled diffusion rate adjustment without altering thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the thickness of the semipermeable membrane is increased to reduce the diffusion rate of biological substances, then the diffusion rate is reduced, but the membrane thickness control becomes inconsistent and requires many coating steps
Solution Approach 1:
The invention changes the hydrophilicity parameter of the polymer membrane by incorporating hydrophilic groups (such as PEG chains) into the polymer structure. This allows control of the diffusion rate through chemical composition rather than physical thickness, resolving the contradiction between achieving desired diffusion control and maintaining manufacturing consistency.
2Reliability
If the hydrophilicity of the polymer membrane is increased to enhance biological substance diffusion, then the diffusion rate increases, but the adhesion to hydrophobic sensor surfaces deteriorates
Solution Approach 1:
The invention applies local quality by creating a polymer structure with distributed hydrophilic segments (PEG chains) among hydrophobic segments. This allows different regions of the polymer chain to provide different functions: hydrophobic regions adhere to the sensor surface while hydrophilic regions facilitate biological substance diffusion, resolving the contradiction between adhesion and diffusion.
Solution Approach 2:
The invention creates a composite polymer structure combining hydrophobic polynorbornene backbone with hydrophilic PEG side chains. This composite structure integrates the adhesion properties of hydrophobic materials with the diffusion-enhancing properties of hydrophilic materials, simultaneously achieving both adhesion strength and high diffusion rate.
3Reliability
If a hydrophilic polymer membrane is used to improve biological substance diffusion, then the diffusion rate increases, but the membrane stability deteriorates due to peeling from sensor surface
Solution Approach 1:
The polymer structure incorporates both hydrophobic segments (for stable adhesion to sensor surface) and hydrophilic segments (for enhanced diffusion). This local differentiation of properties within the same polymer structure allows the membrane to maintain stability through hydrophobic adhesion while achieving high diffusion through hydrophilic channels.
Solution Approach 2:
The composite polymer structure combines the stabilizing effect of hydrophobic polynorbornene with the diffusion-enhancing effect of hydrophilic PEG chains. This composite approach simultaneously achieves membrane stability and high biological substance diffusion rate, eliminating the peeling issue of purely hydrophilic membranes.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The porous structure ensures good adhesion and controlled diffusion of biological substances, enhancing biosensor stability and responsiveness.
Implementation Method 1
during the drying process, the hydrophobic component and the hydrophilic component undergo phase separation
Implementation Method 2
a mixed solution of a hydrophobic polynorbornene polymer material and a hydrophilic small molecule containing a thiol functional group is coated onto the surface of a biosensor electrode and cross-linked
Implementation Method 3
the diffusion rate of biological substances from the external environment to the surface of the sensor electrode
Data Source
Figure 1~2
Figure 3~4
AI summary
Provided by the present invention is a method for preparing a porous polymer semipermeable membrane, wherein a hydrophobic polynorbornene polymer and a hydrophilic small-molecule crosslinking agent containing a thiol functional group are mixed and dissolved in a solvent capable of dissolving both of them to obtain a coating solution; the coating solution is applied onto the surface of a biosensor electrode and dried such that the hydrophobic component and the hydrophilic component undergo phase separation; then, a membrane is formed and crosslinking is carried out, the unreacted hydrophilic small-molecule crosslinking agent is removed, and re-drying is carried out to obtain a porous polymer semipermeable membrane; also disclosed is a product. For the product obtained by the preparation method of the present invention, the hydrophobicity of the polymer enables good adhesion of the porous polymer semipermeable membrane to the surface of the biosensor, and the porous structure ensures the diffusion of biological substances to the surface of the biosensor, and regulates the diffusion rate of the biological substances in the semipermeable membrane without changing the thickness of the polymer membrane significantly.